This is undoubtedly the most disappointing plugin of 2012. Here are my chief gripes.
1. The Facebook app part of the plugin API only becomes active after a few days after the app is created. Until then, you keep shooting in the dark as to why its not working.
2. The subscribe button shows up and even shows subscriber count when used as a widget. But clicking on it cannot get you subscribed. And it will only show in IE!
3. The Like button widget simply will not show, in any browser!
My guess is that this is a very temperamental plugin and it's functionality is largely dependent on the theme being used.
Another good reason why Facebook and Open Source should never intersect.